Multi-tier press with simultaneously opening and closing tiers



W. HUTTER June 24, 1969 MULTI-TIER PRESS WITH SIMULTANEOUSLY OPENING ANDCLOSING TIERS lofS Sheet Filed Sept; 26. 1966 FIGJa WILL HUTTER June 24,1969 I w. HUTTER 3,451,334

MULTI-TIER PRESS WITH SIMULTANEOUSLY OPENING AND CLOSING TIERS FiledSept. 26; 1966 Sheet 3 of 5 FIG. lb

June 24, 1969 w. HUTTER 3,451,334

MULTI- TIER PRESS WITH SIMULTANEOUSQY OPENING AND CLOSING TIERS FiledSept. 26, 1966 Sheet 3 of 5 INVENTOR "MW dag June 24, 1969 w. HUTTER3,451,334

MULTI-TIER PRESS WITH SIMUL-TANEOUSLY OPENING AND CLOSING TIERS FiledSept. 26 1966 Sheet 4 'of 5 FIG. 4

W/LZ. HJTTZ/P w. HUTTER 3,451,334 MULTl-TIER PRESS WI TH SIMULTANEOUSLYOPENING AND CLOSING TIBRS June 24, 1969 Sheet 'Filed Sept. 26. 1966 071;1: A E/ 2 F512 M 4 @ZQ,

xrraR/WEF United States Patent Int. Cl. 153% 7/02 U.S. Cl. 100-200 4Claims ABSTRACT OF THE DISCLOSURE The press has several verticallydisplaceable platens arranged in a single row, between the press tableand a top cross-bar. An arm is pivoted on each end of the cross-bar.Adjustable pairs of pull rods connect pivotably each platen to therespective arms. The pull rods each have hydraulic cylinders forequalizing the pressure on the respective platens.

The present application is a continuation-in-part of US. patentapplication Ser. No. 436,866 filed on Mar. 3, 1965, by the sameapplicant, now abandoned.

The invention relates to a m ulti-tier press with simultaneously openingand closing tiers.

The related industry has developed many different designs for thesimultaneous closing and opening of all the tiers of a multi-tier pressmechanism. In these mechanisms, that construction proved most successfulwherein on two oppositely disposed sides of the press there are mountedarms swingable about a horizontal axis and pressure rods secured to thepress table and linked to the free end of the respective swingable arms,while the individual tier platens are connected by links to theswingable arms. The links or pull levers at the same time extend insuccession downwardly in proportionally reduced lengths, correspondingto the tier platens from the pivot axes of the respective swinging arms.

In order to adjust the individual pull members to the required lengthsbetween the linking points to the corresponding tier platens and theswinging arm there are usually provided tension locks or swivels or asimilarly acting retightening device for each member or [for each pairof members. After the ensuing adjustment of the pull members to theirrequired lengths, the mechanism operates without ditliculty when all thetiers are loaded to exactly the same heights.

In practical application, however, this is not the case. Furthermore itmust always be taken in consideration that each press plate occasionallyhas a too high or too low a charge or may be left empty through anoversight.

In order to overcome the difficulties resulting from an unequal fillingof the press plates it has already been proposed to equip the above pullmembers between the plates and corresponding swinging arms with anhydraulic equalizing device. For this purpose the pivot point of eachpull member was constructed as a double acting hydraulic cylinder, inwhich a piston-like enlarged upper end could displace a rodlike pulllever. According to the known proposal, the space in the cylinder underthe piston end was filled with a liquid or refined medium which acted asa hydraulic cushion. The plate suspended at the piston end of each pullmember acts as a counterweight and pulls the piston end downward untilthe counter pressure reaching the hydraulic cushion equalizes thisweight pressure. In order to attain the intended equalizing etfect eachpiston end is provided with two bores, one

ice

of which is closed by an adjustable relief valve and the other ofsimilarly adjustable return check valve.

The proper installation or adjustment of all relief and check valves,according to the known proposal, requires much time and experience.Furthermore, the individual equalizing mechanism of the pull membersmust be watched because the relief or check valves lose their seals andthe intended equalizing elfect is lost.

The invention obviates these disadvantages. Its purpose is to change thehydraulic equalization mechanisms of the pull members both with regardto construction and function and to completely dispense with relief andcheck valves at the piston-like enlarged upper ends of the pull members,as well as with the corresponding bores through the piston end. Thesolution of this purpose according to the invention residessubstantially in the following:

The invention comprises a hydraulic cylinder for each pull member or,more precisely stated, for the equalizing mechanism of the correspondingswinging arm. According to the invention, however, this cylinder isimpacted only in the direction of the swinging arm by a hydraulicpressure medium and is provided with a hollow piston connected with thepull member and provided with a downwardly extending bush for apiston-like enlarged end of the pull member, said end having no boretherethrough. At the point of transition of its upper bush-like partinto the lower part each hollow piston is provided with a shoulder onwhich normally rests the piston-shaped enlarged end of the respectivepull member. The fill of the cylinder is calculated in such a mannerthat the hollow piston bears with its end directly on the open end wallof the cylinder as long as the hydraulic cushion under it is notcompressed by the weight pressure of the corresponding plate.

Further details of the invention and of the manner of its operation aredescribed in the embodiment examples shown in the accompanying drawing.The drawing illustrates a multiplate press of the above mentioned typeof construction with a mechanism for the simultaneous closing andopening of all plates wherein each plate is provided with a pull memberand hydraulic equalizing device.

In the drawing:

FIG. la is a side elevational view, partly in section, of the press,showing the press in open position and a schematic representation of asingle common accumulator and the connections thereto; FIG. lb is a sideelevational view, partly in section, showing the press of FIG. la inpartly closed position.

FIG. 2 is a side elevational view, on an enlarged scale partly insection, of the press in open position and FIG. 3 is a cross-sectionaldetail of the working cylinder of the equalizing device.

FIG. 4 is a view similar to FIG. 1a, with the employment of twoaccumulators, and

FIG. 5 shows, schematically, an accumulator.

In the illustrated multi-platen press, the upper crossbar 2 is rigidlysecured to the frame 1 mounted on the press base 211 and the lowercrossbar is constructed as a press table 3, which may be raised andlowered, while respective hydraulic cylinders 4 are provided for theupwardly directed movement of the press table 3 and its downward returnwhen the press is opened. The numerals 5, 6a, 61), etc. and 7 indicatethe cover plates of the individual press plates in the direction fromthe top to bottom. The drawing indicates only six plates for the sake ofclarity, while in actual use twenty and more plates may be present. Thecover plate 5 of the upper story and the bottom plate 8 of the loweststory are rigidly secured to the upper cross-beam 2 and to the presstable 3 respectively. The cross-bar 2 is provided at each side with twofork-like arms 9 which are swingable about a horizontal axle 10. Rigidpressure rods 12 extend from the free ends of each of the swinging arms9, the lower ends of these rods being secured to the press table at 13and the upper ends at 11. In order to hold and raise the plates 6a-6band 7, which may be mounted in known manner on the frame support 1,there are provided pull members in the form of rods 14, which are linkedat 15 to the corresponding story plates of the corresponding stories.

Each rod 14 is provided with a turnbuckle, tension lock 16 or the like,by means of which it is possible to make a precise adjustment of thelength of equalizing devices indicated by the numeral 17 pivoted to arms9 at 23. The enlarged piston-like end 18 of each rod 14 is guided in abush-like opening 19 of a piston 20, as shown in FIG. 3. The piston 20is displaceable in a cylinder 21 and is provided with a rod 14 which isguided in the lower part 20a of the lower end 21a of cylinder 21. An eye22 is provided at the upper end wall 21b, by means of which eye thecylinder 21 and thereby the hollow piston 20 and the rod 14 connectedwith its piston end 18 is connected to one of the respective swingingarms 9, as shown in FIG. 1.

At the point where its hollow portion 19 changes from its bush-likeupper portion to a lower portion for guiding the corresponding rod 14,the hollow piston 20 is provided with a shoulder 20b on which normallyabuts a piston-like enlarged top end 18 of the rod 14. The work space ofthe cylinder 21 which is left free between the piston 20 and cylinder 21is impacted with a hydraulic pressure medium through the nipple 24 inthe direction of one of the respective swinging arms 9, thus acting onthe piston 20. The hydraulic pressure medium may enter either upwardlyinto the space between the cylinders 21 and 2012 or be dischargeddownwardly in the space through the nipple 24.

The free circular-shaped work space which is connected to the nipple 24and is left free by the piston 20 is sealed off by the sealing rings 25.This prevents the pressure fluid from entering the piston hollow 19, inwhich the rod 14 with its upper end 18 is freely displaceable. There istherefore no pressure liquid in the hollow 19, which could influence theupper end 18 of the rod 14. Furthermore, the lowest of the sealing rings25 prevents the escape of the pressure liquid from the work space intothe atmosphere. The nipple 24 is closed off by the upper piston end 20when the latter rests on the end wall 210.

The efiFect of the above described equalizing devices 17 depends on theamount of pressure with which the hydraulic fluid is introduced throughthe nipples 24 into or maintained in the work space between thecylinders 21 and pistons 20.

As noted above, difficulties in operation are caused by the unequalfilling of the individual press tiers.

Should the pull members 14 be of rigid construction, Without anequalization device as in the prior art they would bend or be tornapart.

The equalizing devices 17 are therefore provided to shorten or lengthenthe pull members according to the particular loads.

All equalizing devices are functionally the same. The pressure of thehydraulic medium in all these devices is calculated in such a manner,that the force acting on the pistons 20 is somewhat greater than theweight of the platens 611-651, 7, including the filling of the materialto be pressed and the rods 14 and links 15. The equalizing devices thusobtain, the position in FIG. 3, with the hollow pistons 20 abutting theupper cylinder wall 21b, when the press is opened.

Should now one tier be filled too high with material, this material willcontact the next higher tier sooner than anticipated. This next highertier or platen will be raised, while the platen below has a heavierload. The rise of the upper plate requires a shortening of thecorresponding pull member 14. This is effected by the upward movement ofthe pull member in the hollow 19.

The overload of the lower platen and its corresponding load height canbe equalized by having the rods 14 pull the hollow cylinders 20downward, thus lengthening the pull members. Obviosuly, the load on thelower platen will be greater than the force of the pressure mediumacting on the piston 20.

In this manner an equalization is atuomaticailly effected, so that thepress functions without difficulty and no bending or breaking of thepull members will take place.

In one construction, all the equalizing devices may be of the samedimensions. It is thus possible to connect all devices to a commonpressure regulating device. Due to the equal size of these devices, theforce acting on each of the pistons 20 is the same.

FIG. la illustrates schematically a regulating arrangement with devices17 and devices 17. An accumulator a is connected by means of conduits bto the equalizing devices so that this pressure prevails in bothdevices.

It is also possible, if desired to attain an equal force in equalizingdevices of diflerent sizes. In this case however, each device must beimpacted with a correspondingly different pressure.

A particularly advantageous action of the press results, however, whenthe equalizing devices 17 are controlled in such a manner that thepressure medium force acting upon the piston 20, is substantiallygreater than the total sum of the weight of the platen, the material,the bar 14 and the link 15, as in the rest of the devices. Furthermorethe lowest press tier should be left empty, as shown in the example.

A greater force acting on the pistons 20 of the equalizing devices 17can be produced by connecting all equalizing devices to one commoncontrol member, while making the devices 17 of larger dimensions. Sincethe force of the pressure medium acts upon a larger piston surface, theresulting force is much greater.

On the other hand, the devices 17 may be connected to a separatehydraulic pressure medium accumulator, as shown in FIG. 4.

All devices 17 are connected to an accumulator c by conduits 01, whiledevices 17 are connected to an accumulator e by conduits f. Since theaccumulators may be regulated for a certain pressure, the devices 17 maybe controlled independently of one another.

As shown schematically in FIG. 5, each of such accumulators comprises amassive housing 30 for the pressure medium in which is secured aso-called storage nozzle 32 filled with nitrogen. The oil accumulatorsare connected with the equalizing cylinders 17 through the conduits dand 1 respectively and forms a closed hydraulic circuit. Since thegaseous nitrogen in the storage nozzle 32 is compressible, it ispossible to preset a certain pressure in the accumulators, depending onthe quantity of the nitrogen fill, whereby said pressure may furthercompress the pressure liquid flowing in from the equalizing devices 17.It is therefore possible to adjust the pressure with such exactness,that the pressure exerted on the pull members 14 and 14, during theclosing operation of the press, suflices to pull the pistons 20downwardly by the displacement of the pressure fluid. The displacedfluid then flows back into the oil accumulator under compression bystorage nozzle 32. Should the pistons 20 be relieved to such an extentthat the pressure force exerted thereon by the hydraulic pressure mediumis greater than the pulling force acting on the pull members 14, thenthe pressure medium will flow again to the equalizing devices 17 throughthe release of pressure of the storage nozzle 32.

FIG. 5 further shows schematically the details of construction and theconnections of the accumulators to the equalizing devices. Numeral 34indicates a filling device, 36 is a pressure gage, 38 is a connectionfor testing, 40 is a manometer, 42 is a pressure limit valve, 44 is acheck valve, 46 is a high pressure hydraulic pump, 48 is a magneticscreen filter, 50 is a ball type stop valve, 52 is the oil reservoir, 56is an air filter, 58 is a pressure limit valve, 60 is a ball type stopvalve, 62 is another ball stop valve, 64 is yet another ball stop valve.

This press operates as follows:

As usual, all pistons 20 contact the upper end wall 21!) when the pressis open. The closing operation is entirely similar to that of the firstdescribed embodiment. As soon, however, as the press has closedsulficiently to seal the fill material the force acting on the pullmembers 14 and 14' becomes so strong, that all the pistons 20 are pulleddown.

The increased force acting on the pull members 14 is based on the factthat the foot plate 8 of the press table 3 does not yet press from belowagainst the tier plate 7 during this pre-pressing and the pressure forcemay thus be transferred to cylinder 4.

Due to the change in length of the pull members, resulting from pullingout of the piston 20, the footplate 8 of table 3 reaches directly thetier plate 7, so that now the material may be completely compressed,with the full employment of the press pressure produced in the cylinders4.

The advantage of this construction, during closing, resides in the factthat the material is first pre-compressed lightly, while the weight ofall tier plates is completely equalized, so that equal press conditionsare produced in all tiers.

When the press is opened, the cycle is repeated in reverse order. Atfirst only the press table moves downward, while the filled tiers, stillunder the lighter pressure of the equalizing devices 17, remain closeduntil, due to the lowering of the swinging arms 9, the hollow cylinders20 have been moved upward to contact the end walls 21b. This somewhatlonger closed condition under the lighter pressure of the equalizingdevices 17 is advantageous. For example, in pressing under heatconditions, the resulting steam may continuously evaporate. During asudden opening, the press plates may be partially broken as a result ofan explosion-like action. Additionally the quality of the press platesis considerably better when a press plate is not suddenly completelyopened under immediate pressure relief.

It has developed and proven advantageous, particularly for goods of acertain nature to leave empty the lowest press story between the plates7 and 8. It has thus been made possible to have the press table 3 actthrough the pressure rod 12, the swinging arms 9 and the pull membersthrough the rod 14 on the foot plates or bottom plates 6 or 7 of theremaining press story. It is thus possible to also operate very heavymulti-plates presses with small and exact pressures, which is notpossible in comparable known multi-story presses. The following must beobserved in this case: In heavy presses the press table is subject to apressure of 60 t and more in order to subject the press material in theindividual stories to the required specific surface pressures of, orexample 80 kg./cm. Contrarywise, machines of a different type requireonly a very small or very precisely maintained specific surfacepressure. The possibilities of the hydraulic drives of known multistorypresses do not extend far enough to make possible even a 1% adjustmentof the pressure. In the press according to the invention this isaccomplished without any difficulty by leaving the lowest press plateempty. The press table 3 is displaced only to such an extent that theloaded plates are closed and the equalizing devices 17 of these platesprevent an uncontrolled precompression of the pressed material. Theempty lowest plates, the bottom plate 8 of which may consist of only acooling plate, remains open an amount equal to the thickness of thepressed goods. Now the swinging arms '9 are moved upwardly due to thecorresponding impact of the power equalizing devices 17 with thehydraulic pressure medium somewhat further and take along at the sametime all the bottom plates of the filled stories by means of thecorresponding rods 14. The pressure of the mediums in the devices 17 canbe conveniently adjusted in fractions of one atmosphere of absolutepressure so that any desired slow and precisely selected specificsurface pressures may be obtained in the filled stories. FIG. lb, showsthe press after the ensuing compression of the press material While thelowest story limited by plates 7 and -8 is always remaining open acertain distance.

The regulation may be provided by an oil accumulator which may be setfor a certain pressure and is shown in FIG. 5. A storage device 32, forthe hydraulic medium is mounted in the massive housing 30 and is filledwith nitrogen. The accumulator is connected through the conduits b, dand f with the cylinders 17 and 17' and forms a closed hydrauliccircuit. Since the nitrogen in the storage device 32 is compressible, itis possible to set a certain pressure, depending on the fill amount ofnitrogen, which can be further compressed through pressure fluidstreaming in from the equalizing devices 17, 17 in which pulling forceexerted on the rods 14 during the closing of the press suffices to pulldownwardly the pistons 20 under the displacement of the pressure liquid.The displaced fluid flows into the accumulator 30 while compressing thestorage device 32. Should the pistons 20 be relieved to such an extentthat the pressure exerted on them by the hydraulic fluid is greater thanthat on the rods 14, 14, then the pressure medium will flow back whenthe tension of the device 32 is released to the cylinders 17 and 17'.

As shown in FIGS. 1a and 1b, the conduits b are connected to the conduit(in the upper right hand portion of FIG. 5). The conduits d and f arelikewise connected to the conduit 70, as are the devices 0 and e in FIG.4. The conduit d and f leading to devices b and e may be joined togetherin the same manner as shown in FIG. 1a.

What I claim is:

1. Multi-tier press comprising a frame support, a press base, oppositelyspaced vertical frame members extending upwardly of said base, across-beam integral with the upper ends of said members having a bottomportion, a horizontal top platen secured to the bottom portion of saidcross-beam, a horizontally extending press table vertically displaceablebetween said frame members, hydraulic power means for displacing saidpress table, a plurality of horizontally spaced platens displaceablebetween said top platen and said press table, a pair of arms, each armpivotable with one of its ends to the respective ends of saidcross-beam, a pair of rigid pressure rods, each of said rods pivotablyconnecting the other ends of said arms with opposite ends of said presstable, a plurality of spaced pull members, equalizing means securing theupper ends of said pull members to said arms at spaced intervals, thelower ends of said pull members being pivotable to respectiveintermediate platens.

2. Multi-tier press comprising a frame support, a press base, oppositelyspaced vertical frame members extending upwardly of said base, across-beam integral with the upper ends of said members having a bottomportion, a horizontal top platen secured to the bottom portion of saidcross-beam, a horizontally extending press table vertically displaceablebetween said frame members, a hydraulic power means for displacing saidpress table, a plurality of horizontally spaced platens displaceablebetween said top platen and said press table, a pair of arms, each armpivotable with one of its ends to the respective ends of saidcross-beam, a pair of rigid pressure rods, each of said rods pivotablyconnecting the other ends of said arms with opposite ends of said presstable, a plurality of spaced pull members, equalizing means securing theupper ends of said pull members to said arms at spaced intervals, thelower ends of said pull members being pivotable to respectiveintermediate platens, each of said equalizing means comprising acylinder having a closed upper end portion pivoted to said arms and anopen bottom end portion, a hollow piston having an enlarged portionwhich is slidable in said cylinder and through said open bottom endportion, said piston having an outer Wall spaced from the inner wall ofsaid cylinder and forming a chamber therewith, the upper end of saidpull member having an enlaregd piston-like portion slidable in saidhollow piston, inlet means for admitting pressure liquid into saidcylinder, first seal means for sealing said open bottom end portion withthe outer wall of said piston and second seal means in said pistonsenlarged end for sealing said enlarged end with the inner wall of saidcylinder.

3. Multi-tier press as defined in claim 2, wherein each of said pullmembers is provided with turnbuckles intermediate said equalizing meansand the respective platens for adjusting the lengths of said pullmembers.

4. Multi-tier press according to claim 2, further provided with aseparate pressure accumulator for hydraulic medium supplied to theequalizing means of the pull member connected to the lowermost of saidplatens and separate pressure accumultor for hydraulic medium sup-References Cited UNITED STATES PATENTS 3,361,056 1/1968 Carlsson et a1.100-200 2,558,796 7/1951 Tapper 100-109 X 2,586,474 2/1952 Moore 100-2002,884,032 4/1959 Thurnher 100-199 X 2,913,027 11/1959 Thurnhcr 100-200 X2,941,249 6/1960 Rogers 100-199 X 3,009,495 11/1961 Coate 100-199 X3,050,777 8/1962 Siempelkamp 18-16 3,202,088 8/1965 Hammon et al.100-200 X 3,209,405 10/ 1965 Lowenfeld 100-199 X BILLY J. WILHITE,Primary Examiner.

U.S. Cl. X.R. 18-16

